Model Transformations

PAO includes a variety of functions that transform models, which generally are applied as follows:

Here, the function transform_func generates the model new_model from the model old_model. The object soln is used to map a solution back to the old model:

The following transformation functions are documented and suitable for use by end-users:

• pao.pyomo.convert.convert_pyomo2MultilevelProblem()

  This function generates a LinearMultilevelProblem or QuadraticMultilevelProblem from a Pyomo model. By default, all constraints in the MPR representation are inequalities.

• pao.mpr.convert_repn.linearize_bilinear_terms()

  This function generates a LinearMultilevelProblem from a QuadraticMultilevelProblem that only contains bilinear terms. This transformation currently is limited to MPRs that only contain inequality constraints.

• pao.mpr.convert_repn.convert_to_standard_form()

  This function generates an equivalent linear multilevel representation for which all variables are non-negative and all constraints have the same form (inequalities or equalities). This simplifies the implementation of solvers, which typically assume a standard form for subproblems.